"I’m not remotely angry with Tom Watson, I simply want to set the record straight. If anything, I’m just irritated that he can’t seem to hold a confidence when he is meant to be probing serious wrong doing," Thurlbeck wrote.

Thurlbeck also said News of the World journalists had "grave reservations" about carrying out surveillance on MPs, stressing that decisions were taken by News International executives, over the head of editor Colin Myler and without Rebekah Brooks' knowledge.